Flowmeter for hydrofluoric acid



3811- 1944- M. P. MATUSZAK FLOW METER FOR HYDROFLUORIC ACID Filed Jan.29, 1942 Patented Jan. 25, 1944 UNITED STATES PATENT OFFICE FLOWMETERFOR HYDROFLUORIO ACID Maryan P. Matuszak, Bartlesville, Oklau 35 8110 1,

to Phillips Petroleum Company, a corporation of Delaware ApplicationJanuary 29, 1942, Serial No. 428,786

' 2 Claims. (cl. 73-205) sures, have been used as flow meters fornumerous fluids in the past. In these flow meters, however, the fluid isallowed to come in contact with glass. Such flow meters areunsatisfactory for measuring fluids that, like hydrofluoric acid, aredestructive to glass.

My present invention discloses means by which the corrosive fluids inquestion may be prevented from coming in contact with any portion of theinstrument which might sufier damage thereby. My invention furtherdiscloses means by which parts susceptible to attack by the corrosiveagent may be entirely eliminated.

In the past, the measuring of hydrofluoric acid, anhydrous or aqueous,has been by elementary and crude methods that were adequate only forbatch utilization of the acid; for example, the acid could be stored insuitably resistant containers, and the quantity used for any particularoperation could be determined by weighing the container. Lately, theacid has been found to be useful in certain processes, notably inpetroleum treating, and the problem of introducing the acid in acontinuous controlled manner conducive to efilciency in large-scaleoperations thus arose. My present invention,

therefore, is a contribution to the art of instrumentation generally,and to the handling of cor rosive materials in particular.

An object of this invention is to provide a flow meter suitable formeasuring streams of hydrofluoric acid.

A more specific object is to provide a means for measuring the flow ofcorrosive materials, es-

pecially hydrofluoric acid, without the use ofwhich the fluid flowson'passlng from the one to the other and on the other hand, by adiflerential pressure-responsive means comprising two bellows thatindicate the pressure drop across ,the orifice.

The accompanying drawing is an elevational view of an illustrativeembodiment. of my invention.

Certain general features of this invention may be regarded asbeingespecially useful in such devices. Thus, when the flow meter is in.use,

the fluid being measured enters by inlet ll,

passes through orifice l2, and leaves the flow meter by outlet l3.Orifice I2 maybe of any desired type known to the art; it provides aresistance to flow that manifests itself by a drop in the pressure ofthe fluid. T pressure drop or difierential pressure aifects theequilibrium position of bellows I4 and I5, preferably of the-type ofSylphon" bellows, which communicate with inlet H and outlet l3 byconduits l6 and ll, respectively, and which are connected to each otherby means, more particularly described hereinafter, in such a way thatcontraction or expansion of one bellows is accompanied by acorresponding expansion or contraction of the other.

Since the pressure drop varies with the rate of flow of the fluid, theequilibrium position assumed by bellows l4 and I5, after suitablecalibration of the flow meter, indicates the rate of flow of the fluid.

All parts of the flow meter, including the two bellows, that arecontacted by the fluid should be constructed of suitable resistantmetal, preferably of an alloy, such as high-nickel steel, that isespecially resistant to attack by hydrofluoric acid. All jointspreferably should be welded; solder and brass should be avoided.

In the embodiment of the drawing, closed ends l8 and I9 01' bellows l4and [5 are Jointedly connected to beam 2| at beam ends 22 and 23, re-

7 spectively. At these ends, beam 2| moves incorrespondence withmovements of the closed ends of the bellows, but at its mid-point it isfixed in position by pivot pin 24, around which it can move through onlya limited angle that is determined by the limits of movement of theclosed ends of the'two bellows.

duit l6 and/or conduit H, and which is of such dimension in thedirection of. expansion and contraction of the two bellows that thesehave thelargest practicable or permissible range of movement. A tensionmeans, such as coil spring 26, is attached to beam 2| at a pointconsiderably in 24 is held fixedly-,1 ln position by ar 25, which isattached to cod:

removedirom the mid-point, as by means of a hole in beam 2| at point 21and a setserew II, and to a fixed point, not on the beam, preferably pin24. .The tension exerted by coil spring 28 is so adiusted that, when thepressure in each bellows is identical (that is. when there isno flow offluid through orifice Ill, bellows ll is can. tracted and bellows I! isexpanded, each to about the maximum permissible extent.- When thebellows are in this condition, pointer 29, attached to beam 2|, pointsto zero on graduated scale It, which is positioned in fixed relationshipto arm 2! by means not shown that may be readily supplied by thoseskilled in the art. when a fluid is flowing i'rom inlet ll throughorifice II to outlet ll, the resulting diflerence in pressure across theorifice causes bellows II to expand and bellows it to contract until anew equilibrium position, determined in part by the tension exerted onbeam II by coil spring 28, is reached; pointer 2| correspondingly movesalong-scale II, and thus, aiter calibration of the flow meter by any 01the various suitable methods known to the art, indicates the rate offlow oi the fluid.

The drawing shows one embodiment in the condition assumed when the flowoi fluid is at about the middle of the permissible range of flow.The-actual range covered by any particular em- It will be understoodthat the drawing is schematic, and that many changes, variations, andrefinements may be made in the embodiments illustrated. Because 0! themany modifications that may be made, the'invention should not be undulylimited 'by' the illustrative embodiment described hereinbei'ore, but itshould be limited only in accordance'with the appended claims.

I claim:

1. A difierential pressure meter used for measuring the rate or flow oicorrosive fluids containing hydrofluoric acid comprising, in combinationwith a conduit through which said fluid flows and which has arestricting orifice for eilecting a pressure drop, a first bellows whichis resistant to the action of hydrofluoric acid fluid-connected to saidconduit upstream from said orifice, a second bellows likewise resistantto the action of hydrofluoric acid fluid-connected to said conduitdownstream from said orifice, said bellows being arranged with theiraxes parallel, a pivot pin, a beam pivoted at its mid-point about saidpivot pin, a fixed scale, a pointer fixedly carried by said beam at anangle thereto and at the middle of said beamand arranged to registerupon said fixed scale, said bellows each having one end fixed and theother free and closed end pivotally attached to the ends of said beam, acoil spring bodiment is mostly determined by the size or orifice l2,which, therefore, may be varied in ac 3 cordance with any particularflow requirement. The range may be modified or adjusted to some extentby proper selection of coil spring 28. Such adjusting is believed to bewell within the ability of those skilled in the art of using flowmeters.

The bellows usually may be advantageously positioned so as to readilydrain free from the fluid being measured, when the flow meter is takenout 01! use, as particularly shown in the drawing; however, they may bepositioned otherwise, ii desired. Similarly, the entire flow meter maybe used in positions other than those specifically shown in the drawing,as will be readily understood by those skilled in the art.

having one end attached to said beam at a point therein between saidmid-point and .an end of said beam and the other end attached to saidpivot pin and arranged to cause contraction oi saidbellows connected tosaid upstream side and expansion of said bellows connected to thedownstream side of said orifice but to allow expansion of said firstbellows and contraction of said second bellows when a fluid passesthrough said conduit. Y

2. The apparatus 0! claim 1 wherein all parts contacted by the fluid theflow of which is being measured are constructed of high-nickel steel andthereby especially resistant to attack by hydrofluoric acid.

. MARYAN P. MATUSZAK

